Barcelona
Sagrada Familia is the greatest unfinished work by Antoni Gaudi it is a little smaller than MontJuic because the architect didn't want to compete with nature and he said that man should never build something grater than God created.
There are great museums, parks (Park Guell is the greatest), historical buildings, beach and of course restaurants aquarium and gift shops. In 5 days I did manage to go to all major sites and will post pictures from all of them in the coming days.
I recommend 7 days to visit Barcelona because there is so much to see and the tourist objectives are nor near each other, so you will have to travel a lot by bus and subway or train.
10 trips with local transport around town cost 10.50 Euros.
Of course there are more eccentric ways to get around one of them is with a Galardo or a 458 Spyder for about 69 Euros for 20 minutes :)
This is Antoni Gaudí's spectacular vision that is under construction for more than a century now. The interior is simply breathtaking.